Method of and apparatus for controlling arc welding



June 16, 1925.

R. L. KINGSLAND METHOD OF AND APPARATUS FOR CONTROLLING ARC WELDING.Filed Aug. 15. 1921 mantel nl zo fi/t QZNYflnJY win won y I clunPatented Junel6, 1925.i 1,512,792

UNITED STATES PATENT OFFICE. 1 2 mm L. KINGSLAND, or min mum, wnsrvraemm. M'EI'HQD 01 APPARATUS FOR CONTROLLING ARC WELPING. I Applicationfiled August 15, 1921. Serial No. 492,439. I

To all whom it may concern: age source and will limit the length to Beit known that I, ROGER L. KINGSLAND, which the arc may be drawn, and atthe a citizen of the United States of America, same time furnish to the'arc the current residing at Fairmont, in the county of necessary togive the required heat to the. 5 Marion and State-of WestVirginia, havearc.

invented certain new and useful Improve- I have found that the arebetween the 'ments in Methods of and Apparatus for work and electrodewill be concentrated and Controlling Arc Welding, of which thefolstead/y up to an arc length of approximate- I lowing is aspecification. ly 5 16" although this value may vary 10 My inventionrelatesto a means and ufider different conditions and much above methodfor controlling a welding arc in that the arc begins to waver andfinally which it is desired to reduce and limit the roams from theelectrode to any point on voltage at the arc below'that of the source Ithe work within such distance as the voltof supply and to limit thelength of which age and condition of the arc can maintain. '15 the arcmay be drawn. At the same time I find that the metal from There are'what may be termed a long the 'electrode and ofthe work is not burnedarc and a short arc that is the long or oxidizpd. By employing means inconarc maintains sufiicient energy to permit junction with a currentcontrolling means the operator to separate the electrode a to limit thelength of the welding are by 2 long distance from the work after the arelimiting the voltage thereacross, I am able is once established beforethe arc will break. to prevent the operator from burning or This is truewhen the electrode is merely in oxidizing the work and metal depositedand series with aresistance to reduce the curfrom using a long arc whichprevents rent in the arc and connected to a 500 volt the concentrationof the'arc and hence tends 25 source of energy as is the casein usingthe for a cooler arc and prevents roaming current from a trolleyin-welding the rails. of the arc thereby permitting the operator A longare is of a disadvantage in that the to apply the arc to the spotrequired, all 7 arc, laden with conducting-particles of cartending fora. better weld. bon, iron or other metals depending on the There arevarious arrangements and electrode used, will waver or roam schemes forcontrolling the welding arc, after the electrode has separated from thesome comprising-motor-generators of vawork a sufiicient distance and theare not rious designs and characteristics, and which 80 beingconcentrated and steady, the material transform the voltage at thesource to the I of the electrode, when a metallic electrode requiredvoltage at the are; others are 35 is used, will not be deposited over alimited simply a resistance between the source and area, but it will befound in the form of the are which does not control the voltage smallbubbles or deposits of metal around of the arc but merely cuts down thecurrent the work, and at the same time the metal delivered to the arc tothe proper amount. from the electrode and the work itself may Themotor-generator scheme or a gener- 40 be burned or oxidized. ator drivenby gasoline engine, which is not A short are will not do this as it isuncommon, is quite expensive; and the seclimited as to the maximumvoltage across 0nd scheme, merely of a resistance interthe arc and,hence is limited as to the disposed in series between the arc and sourcetance the electrode may be separated from 'of supply, does not give thenecessary re- -the work before the arc will break. My in.- duction andlimitation in voltage, length vention is for the purpose of limitingsuch of arc and characteristics of the ,arc unless v 'voltage across theare when the energy for the source of supply s of proper voltageto 5 thearc is taken from a relative high voltbegin with. j i

3 ing drawing- With my method and apparatus I employ an inexpensive aparatus and reduce the supply voltage an the current'from any amount downto the required are voltage and current and limit the maximum of each tothat required .to give a predetermined maximum length of are, assumingthat the source. of energy is substantially constant. My invention isparticularly adapted to the welding of fish plates and rail .bonds torails where it is desired to utilize the current of the trolley which isusually about 250 volts in mines and 500 to 600 volts or higher forelectric railways and the low voltage are is required.

' In the figures set forth in the accompany- Fig. 1 shows my inventionand it's application to the welding of a rail bond to a rail when thecurrent is taken from the trolley.

.Fig. 2"shows my invention and its application to the welding of twoplates (or other articles) in which the current is taken from agenerator of higher voltage than the arc voltage.

Fig. 3 shows my invention and its application to the welding of twoplates (or other articles) in which I employ means for convenientlyvarying the arc voltage at will.

In the disclosure illustrated in Fig. 1, D is a generator having oneside connected by the conductor 1 to the ground G and the other sideconnected to the trolley T. R represents a resistance element placed inseries with the trolley T and the rail 4 4 by means of the conductors 2and 3, and of suflicient capacity to withstand the required weldingcurrent without undue heating. The rails H are connected to the groundby G. An electrode 6 is connected by the conductor 7 to the resistanceR, at the point 8.

-- This point 8 is determined by experiment or are. 5 0"- R and R, tothe requirements, the operator strikesan are between the electrode 6 andthe work 4. The current flows through R and divides at 8 and part flowsthrough R and the arc. R is adjusted to give the proper current throughthe arc and It" is adjusted to allow the voltage across the arc to reacha predetermined maximum value as the electrode is drawn-away from thework before the arc will break, but when the maximum distance andvoltage have been reached the arc will break causing the operator toagain strike an arc. R" therefore limits the length of the are as well"as the voltage across the are as one is a function of the other.

As the electrode contacts with the work it acts as a short circuit tothe shunt R and most of the current flowing through R will flow throughthe circuit 7 and the work, but the instant the electrode is drawn fromthe work a small amount an arcis produced and maintained, and there is adifference of potential between the electrode and work and the currentflow through R is greatly increased and likewise greatly reduced throughthe circuit 76 and the are. As the arc is lengthened the drop across thearc will increase and also the resistance of the arc and the currentwill become less through the arc and greater through R. Finally thelength of-the arc will become so great that the voltage there-acrosswill have approximated the limit set by R at which time a still largerportion of the current will be flowing through R" that was formerlyflowing through the arc and hence the heating effect of the arc will bereduced as the heat 'is the function of the current squared. As

the arc length is increased by the operator,

the resistance of the arc will increase until its resistance and that ofR" become substantially equal when a very unstable condition will bereached and the current flowing will not be able to sufliciently chargethe are with conducting particles from the electrode to'maintain the arcand it will break and all the current will then flow through Rf and B".By setting the maximum voltage across the are which can be maintained,the maximum length of the arcis set and the operator is compelled towork between the limit of no are by contact and no are by excess lengthand between these .limits the conditions for good welding areestablished and will be maintained.

A very simple, inexpensive and light arrangement of my invention can beprovided in a carrying case which Wlll be capable of reducing thevoltage at the are over a very wide range from that of the source ofsupply. The shunt R" around the welding arc controls and regulates thesame.

It will be apparent that in Fig. 1 the circuit 1 can be connected to theleft hand end of R" in place of the ground.

In Fig. 2 is shown an adaptation of my invention to the welding of otherarticles than rails or rail bonds and where the circuits are. notgrounded. In this case the conductor'l leads to the work 99' to bewelded which is the only difference from the arrangement shown in Fig.1.

In Fig. 3 is shown an arrangement embodying my invention in which isshown a variable resistance R in place of the fixe resistance R" 'in'Fig. 2. The resistance R" of Fig. 3 can also be substituted for theresistance R.oat Fig. 1. ,By operating the handle 10 in Fig. 3 theresistance R is varied and hence the voltage drop across the arc will bevaried. The voltage across the arc may be varied in thearrangement shownin Figs. 1' and 2, but not as conveniently as by the arrangement shownin Fig. 3, by connecting the conductor 7 to the resistance R atdifierent points.

The mounting of my invention in a suitable frame or support is not shownas there:

are many ways of doingthis well known at the present time. There aremodifications of my invention, other than herein described and shown inthe attached drawing and which will be obvious to one skilled mthe artand therefore I do not wish to be limited except by the followingclaims.

I claim: 1. An arc welding system comprising a source of energy, aresistance connected across the source of energy and connections forsupplying energy to awelding are connected to one end of the resistanceand to a point intermediate the ends of the resistance, one portion ofthe resistance limiting the maximum currentflowing. to the welding arcand the other portion of lower resistance than that of'the'first portionlimiting the maximum voltage across the are when welding.

2. An arc welding system comprising a source of energy, a resistanceconnected across the source of energy and connections forsupplyingenergy to a welding are connected to one end of the resistanceand to a point intermediate the ends of the resistance, one portion oiless'resistance than the other portion forming a shunt across theworking arc to cause the arc to 'break when the drop in voltage acrossthe arcrhas reached a predetermined maximum amount.

3. An arc welding system comprising a source of energy, a welding areconnected to the source of energy and with a resistance in series tolimit the maximum current flow: ing through the arc and a shunt of lowerresistance than that of the first said resistance across the arc tolimit the length'to which,

the arc can be drawn when welding.

4. An arc welding system comprising a source of energy, a welding arc:connectedto the source of energy and with a resistance in series tolimit the maximum current flowing through the arc and a variable'shuntresistance across thearc to limit the length of the arc to which it candrawn and to.

vary the limit atwill.

source of energy, a welding arc connected across the source of energyand-in series with a resistance to control the amount of to limit themaximum current through, the

arc and a resistance element of lower resistance than that of the seriesresist?ce connected across the arc to limit the m ximum length to whichthe arc may be drawn.

7 The combination with a welding arc, of a source of substantiallyconstant potential for supplying current to said are, a singleresistance in series with said source, and means for connecting said arein parallel with a portion only of said resistance toprovidea limitedvoltage on said are, the resistance in parallel with said are beingindependent of the current flowing in sai arc. 3 8. The combination witha welding arc, of a source of substantially constant potential fprsupplying current to said arc, a re-' sistance in series with saidsource, means for connecting said are In parallel with a portion only ofsaid resistance of value less than half the total value of saidresistance to provide a limited voltage impressed on' said source, theamount of resistance in parallel with said are being independent of thecurrent flowing in said arc."

9. In arc welding apparatus, the combination of a source ofsubstantially constant potential materially greater than that requiredfor arc welding, a resistance in series with said source, a welding are,means for connecting said are parallel with 'a portion only of saidresistance of a value less than half the total value of said resistanceto produce a said are and thus limit the length thereof, saidconnectingmeans maintaining the value of said resistance in parallel with said areat less than half'the total value of said se- 1es resistance duringwelding operation.

10. In combination with a welding arc, asource of substantially constantpotential limited. voltage on of greater value thanthat required to'operate said are, resistance in series withsaid source, means forconnecting said arci'n parallel with a portion' of said resistance togive a limited potential drop acrosswsa id arc to 'limit the length ofsaid are, saidcoiinecting means maintaining a constant resistance valuein parallel with said are at all times while ,the electrodes of said arcI are separated from one another. 5. An arcwelding systerricomprising a11. In combination, a source of substan- .tially constant potential, aresistance in series with said source, a ;welding are, reparallel withsaid are to remain substantialsistance in eries with said first namedrely unchanged even when said are is broken,

sistance, an means for connecting said thus limiting the voltage on saidare and 1 Welding arc. in parallel with said second consequently thelength ther f. named resistance, said connecting means in- In testimonywhereof I aflix my signacluding means for varying the length of ture.

said are while permitting the resistance in ROGER L. KINGSLAND.

